Processes of producing acrylic acid esters



Patented Oct. 27, 1931 aszazos v reo STATES PATENT OFFICE WALTER, BAUER, OF DABMSTADT, GERMANY, ASSIGNOB TO BCHM & HAAB AKTIEN- GESELLSCEAF'I', OF DABMSTADT, GERMANY, A CORPORATION 01 GERMANY PROCESSES PECDUCIN G ACRYLIC ACID ESTERS Ho Drawing. Application filed Kay 27, 1929, Serial No. 888,588, and in Germany .Tune 18, 1928.

My invention relates to processes of pro ducing acrylic acid ester.

The saponification of nitriles in the pres-.

ence of an acid is well known, and b well- 5 known process nitriles can also be irectly' 7 be esterified in an acid medium by being heated to temperatures, at which water is split off, while at the same time unsaturated esters are formed. If, for instance, concentrated sulphuric acid is employed as the a ent for splitting off water, 120 to 17 0 have been 20 found to be suitable temperatures for the present purpose.

Further, I have found that the process by the use of small amounts of water can be expedited. Such amounts of water can, for in stance be introduced into the process by the use of concentrated acids having a small water content.

Ewample 43 kilograms of ethylene cyanhydrin are carefull mixed with kilograms of methanol an 85 kilograms of sulphuric acid having a specific gravity of 1.80 and are gradually heated to 160 C. while bein stirred.

85 First, some methanol distills o having mixed therewith slight amounts of acrylic acid ester and water. Ihereupon, an acrylic acid ester of a rather high percentage mixed with water and methanol results. Because the water also distills ofl', the process is practically complete and one succeeds in obtaining an output of about 90% of acrylic acid ester.

The process can be practiced at atmospheric pressure or at a pressure difierent therefrom.

In place of the hydroxyl containing nitriles (e. cyanhydrin), their derivatives, e. g. ami es or B-alkoxid compounds can be used.

I claim:

1. The rocess of producing acrylic acid ester whic consists in converting aliphatic fl-hydroxy-nitriles into unsaturated esters in the presence of aliphatic mono-hydrox alcohol and an acid medium which splits o 5 water.

2. The process as specified in claim-1, in which a temperature of 12017 0 C. is maintained. I

3. The process as specified in claim 1, in go which ethylene cyanhydrin is used as initial substance.

In testimony whereof I afiix m signature.

WALTER AUER.

s r l l 

